Unusual presentation of acute encephalopathy with biphasic seizures and late reduced diffusion in Miller-Dieker syndrome.

Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is a unique subtype of acute encephalopathy that occurs in children. A girl aged 2 years and 8 months with Miller-Dieker syndrome (MDS) was admitted for status epilepticus and high fever. Brain MRI performed on the third day postadmission showed abnormally high intensities in the subcortical white matter on diffusion-weighted images. Acute encephalitis/encephalopathy was diagnosed based on the electroencephalography (EEG) findings of diffuse high-voltage delta waves. Six days postadmission, frequent apnoeic episodes were observed, with oxygen desaturation due to cluster seizures. Subclinical seizures were found on amplitude-integrated EEG (aEEG). The disturbance of consciousness was difficult to recognise because of severe developmental disabilities due to MDS. EEG aids in the evaluation of consciousness, and aEEG can be helpful in monitoring and controlling subclinical seizures in the biphasic phase of AESD, especially in patients with underlying neurological disorders.